Advanced Array Methods(filter)

filter

: Creates a new array

  Iterates through an array

  Runs a callback function on each value in the array

  If the callback function returns true, that value will be added to the new array

  If the callback function returns false, that value will be ignored from the new array

function filter(array, callback){

var newArr = [];

for(var i = 0; i < array.length; i++){

if(callback(array[i], i, array)){

newArr.push(array[i]);

}

}

return newArr;

}

/*

Write a function called filterByValue which accepts an array of objects and a key and returns a new array with all the objects that contain that key.

Examples:

    filterByValue([{first: 'Elie', last:"Schoppik"}, {first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Matt', last:"Lane"}, {first: 'Colt', last:"Steele", isCatOwner: true}], 'isCatOwner') // [{first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Colt', last:"Steele", isCatOwner: true}]

*/

function filterByValue(arr, key){

    return arr.key[isCatOwner] === true;             > return arr.filter(function(val){

        > return val[key] !== undefined;

}                                                                 > });

/*

Write a function called find which accepts an array and a value and returns the first element in the array that has the same value as the second parameter or undefined if the value is not found in the array.

Examples:

    find([1,2,3,4,5], 3) // 3

    find([1,2,3,4,5], 10) // undefined

*/

function find(arr, searchValue){

> return arr.filter(function(val){

    return arr === searchValue;      > return val === searchValue

}                                              > })[0];

/*

Write a function called findInObj which accepts an array of objects, a key, and some value to search for and returns the first found value in the arrayt.

Examples:

    findInObj([{first: 'Elie', last:"Schoppik"}, {first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Matt', last:"Lane"}, {first: 'Colt', last:"Steele", isCatOwner: true}], 'isCatOwner',true) // {first: 'Tim', last:"Garcia", isCatOwner: true}

*/

function findInObj(arr, key, searchValue){

    return arr.filter(function(key, searchValue){  > return arr.filter(function(val){                  

        return val[key] === searchValue[0];      > return val[key] === searchValue;                

    });                                                      > })[0];

}

/*

Write a function called removeVowels which accepts a string and returns a new string with all of the vowels (both uppercased and lowercased) removed. Every character in the new string should be lowercased.

Examples:

    removeVowels('Elie') // ('l')

    removeVowels('TIM') // ('tm')

    removeVowels('ZZZZZZ') // ('zzzzzz')

*/

function removeVowels(str){

    var removeArr = str.remove();

      var vowels = "aeiou";

return arr.filter(function(vowels)   > return str.toLowerCase().split("").filter(function(val){

}                                                  > return vowels.indexOf(val) === -1;

> }).join("")

                 > }

/*

Write a function called doubleOddNumbers which accepts an array and returns a new array with all of the odd numbers doubled (HINT - you can use map and fitler to double and then filter the odd numbers).

Examples:

    doubleOddNumbers([1,2,3,4,5]) // [2,6,10]

    doubleOddNumbers([4,4,4,4,4]) // []

*/

function doubleOddNumbers(arr){

    return arr.filter(function(val){

return val % 2 !==0;

> }).map(function(val)

> return val*2;

> })

> }